Doors allow the player teleportation across the level without having rooms placed together. They also can play a transition animation.
Press the Door button on the toolbox
By default, doors have no visuals.
Select your door and add a StaticMesh component to it to add the door visuals
Create a second door where this one should teleport to or duplicate the existing one.
To establish a relationship between the doors, each door should reference each other in the ExitDoor variable on the Details panel
The doors should now work.